The move to a new port would mean the vast number of Apple accessories currently in circulation, including docking stations and speaker systems, would need to be replaced unless adapters are made available.

Photos in circulation among technology media sites purporting to be a prototype case for the iPhone 5 are believed to show the new connector, which looks similar in size to a mini USB port.

It is believed to have a triangle-shaped wedge at one end preventing it from being plugged in the wrong way.

Apple earlier this year advertised for staff to design an "appropriate connection technology" for future products.

"This will often involve adaptation of existing connectors or complete new designs," the company said.